THE WOKK OF FRUITS 317
How does this reach' them? A squash or a pumpkin
is a favorable object for study : it may take up as
much as a pound and a half of water in twenty-four
hours. Cut a young growing- squash from the vine
and place the cut end in eosin solution, and allow it
to stand for several days. Trace the eosin up through
the bundles to the seeds. Do you find a bundle reach-
ing to each seed ? Does the bundle grow larger as the
seed develops? Does the fruit lose water by transpi-
ration? Test this matter in the fashion already
described for leaves. Do you find any stomata in the
epidermis of the fruit (examine microscopically and
also test in the air-pump). Grapes are of especial
interest in this connection: examine also apples,
pears, etc. Admirable means of protection against
transpiration are found in the thick, woody walls of
nuts, drupes (Peach, Eucalyptus, etc.).
Does the fruit need a supply of air? Repeat the
experiment shown in Fig. 31, using immature fruits
instead of seeds. Try the effect of smearing over
young fruits completely with vaseline: does it retard
their development? Do they contain much air in
their tissues ? Place some of the tissue (preferably a
piece of watermelon flesh) under water in the air-
pump, and exhaust.
How does the air travel through the stalk, etc,, to
the fruit? Investigate by the methods previously
described.